#include <iostream>
#include <list>
#include <iterator>
#include <numeric>
#include <cmath>
#include <functional>
#include <algorithm>
using namespace std;
unsigned long no_of_students =0;

double compute(const list<double>& data) {
	double avg = accumulate(data.begin(), data.end(), 0.0) / data.size();
	list<double>::const_iterator it = data.begin();
	double positive = 0.0;	
	double negative = 0.0;
	while(it != data.end()) {
		if(*it >= avg)
			positive += (double) (long) ((*it - avg)*100.0)/100.0;
		else
			negative += (double) (long) ((avg- *it)*100.0)/100.0;
		it++;
	}
	return max<double>(positive, negative);
}

/* main
 *  * */
int main() {
	double exchange = 0.0;
	list<double> data;	
	cin >> no_of_students;
	while(no_of_students != 0) {
		data.clear();	
		while(no_of_students-- > 0) {
			double amount;
			cin >> amount;
			data.push_back(amount);
		}
		exchange = compute(data);
		cout.precision(2);
		cout.setf(ios::fixed,ios::floatfield);
		cout << "$" << exchange << endl;
		cin >> no_of_students;
	}
	return 0;
}
